The aim of this study is to contribute to the development of a simple and quick methodology of extracting surface energy fluxes and evapo-transpiration, from remote detection data in the Northern-east of National W Park of Niger republic, where based ground data are practically unavailable. The methodology adopted is based on the algorithm METRIC in solving the surface energy balance equation using remotely-sensed data of Landsat7 ETM+ and few ground based data. The algorithm involves NDVI, surface temperature and albedo in the input. The obtained results permit the analysis of surface energy fluxes in function of land occupation/use. Areas subject to severe hydrous stress are identified by analysing the correlation between surface temperature and NDVI. The methodology developed here is an important tool for a diachronic study of surface energy fluxes by using many Landsat7 images. Such study is preponderant for a good management of vegetal and hydrological resources of the Park, which is facing, nowadays, to combined effects of natural climate variability and anthropogenic actions.